MC is a lonely student with a boring life, strongly willing to find friends and bring some action into his routine. However, he cannot imagine that he is going to meet his lost childhood friend, Sayori, and this meeting is going to turn his life upside down. MC meets new friends, takes part in spy action and gets involved into the shadow war between the secret service team «IMF Junior Unit 7/13» (codename «Heartbeat») and the criminal organization, known as «The Halictidae».